Explosive pellets are used downhole to fracture rock formations and thereby enhance petroleum recovery. It is difficult to machine an explosive pellet due to its complex shape, brittleness, and concerns about safety. Therefore, pellets are often manufactured by pressing explosive powder in a mold to form a solid pellet. Control of the density distribution of the pellet is critical for optimal performance. Specifically, concentricity of the distribution and consistent longitudinal distribution of the powder from one pellet to the next are the two main characteristics governing the performance of the pellet.
It is very difficult to determine the extent of pellet performance after detonation in a wellbore. Thus, a particular pellet configuration must be carefully designed, manufactured, and tested before deployment. Past inspection techniques include employing physical inspections, scanning electron microscopes, and X-ray scanning technology. Both scanning electron microscopes and X-ray technologies have limitations as the resultant images are grey-scale images containing details not discernable to the human eye yet important to pellet performance. It is thus difficult to isolate and identify faults within a given explosive pellet batch due to either manufacturing faults or design anomalies.
It should be understood, however, that the specific embodiments given in the drawings and detailed description thereto do not limit the disclosure. On the contrary, they provide the foundation for one of ordinary skill to discern the alternative forms, equivalents, and modifications that are encompassed together with one or more of the given embodiments in the scope of the appended claims.